Louise Littig Sloan (May 31, 1898 – March 1, 1982) was an American ophthalmologist and vision scientist. She is credited for being a pioneer of the sub-division of clinical vision research, contributing more than 100 scientific articles in which she either authored or co-authored. Her most notable work was in the area of visual acuity testing where she developed and improved equipment. Sloan received her Ph.D. from Bryn Mawr College in experimental psychology. She spent a short period of time in both Bryn Mawr's experimental psychology program as well as the Department of Ophthalmology at Harvard Medical School. The majority of her career, however, was spent at Johns Hopkins Wilmer Eye Institute where she directed the Wilmer Laboratory of Physiological Optics for 44 years. In 1971, Sloan w